High power, radio frequency (RF) transistor devices are commonly used in RF communication infrastructure amplifiers. These RF transistor devices typically include one or more input leads, one or more output leads, one or more transistors, one or more bias leads, and various bondwires coupling the leads to the transistor(s). In some cases, input and output circuits also may be contained within the same package that contains the device's transistor(s). More specifically, an in-package input circuit (e.g., including an input impedance matching circuit) may be coupled between a device's input lead and a control terminal (e.g., the gate) of a transistor, and an in-package output circuit (e.g., including an output impedance matching circuit) may be coupled between a current conducting terminal (e.g., the drain) of a transistor and a device's output lead.
Instantaneous signal bandwidth (ISBW) is becoming a major requirement for RF communication infrastructure amplifiers, and thus for the high-power RF transistor devices included in such amplifiers. Along with an impedance matching circuit, an RF device's output circuit also may include a baseband decoupling circuit configured to provide an RF ground down to envelope frequencies. Generally, the ISBW of the device is limited by the low frequency resonance (LFR) caused by interaction between the device's bias feeds and components of such a baseband decoupling circuit. In recent years, RF transistor devices have been developed with limited LFRs in the range of about 450 megahertz (MHz) or less, which supports ISBWs in the range of about 150 MHz or less. Although these devices are sufficient for some applications, the desire for wider RF bandwidth amplifiers continues to increase.